CPU: Control Unit, ALU, Clock

• Computer follows an Input -> Process -> Output sequence, with storage needed during processing.

CPU (Central Processing Unit)

• The CPU is a microprocessor that manages work.
• Key components are the Control Unit, Arithmetic and Logic Unit (ALU), and the Clock.

Control Unit

• Manages operations done by the CPU.
• Receives instructions arriving at the CPU.
• Deciphers the meaning of the instructions.
• Directs other CPU components to execute instructions.

Arithmetic and Logic Unit (ALU)

• Performs all calculations within the CPU.

Clock

• Sends out regular electrical pulses.
• Controls CPU operation timing.
• Ensures instructions execute in sync.
• Measured in Hertz (Hz), indicating cycles per second.
• Memory is joined to CPU by buses

Buses

• The CPU's parts are joined by buses.
• High-speed connections carry data inside the CPU.

Data Bus

• Transfers data between the CPU, memory, and other components.

Address Bus

• Carries memory addresses from the CPU to locate data.

Control Bus

• Sends control signals to coordinate operations.

Memory (RAM)

• Connected to the CPU by buses, storing instructions and data.
• The CPU fetches instructions from memory, executes them, and stores results back.
• Memory contains microscopic electrical circuits that are ON or OFF (binary).
• Data is stored using electrical signals.
• When power is lost, memory content disappears (volatile memory).
• Saving work copies it from memory to storage.

Storage

• Hard disk from computer
• Cloud storage
• Flash memory drive

RAM Characteristics

• Fast and close to the CPU.
• Data is lost when power is off.

Secondary Storage

• Data is safe even when power is off.
• Slower than RAM.

High Level Code

• Programming languages easier for humans to read/write (Python, Java, C++, JavaScript).
• Translated into machine code (binary) for CPU execution.

Source Code

• Original human-readable code written in a high-level programming language

Translation Methods

• Needs translation because cannot be executed directly by a computer

Compiler

• Translates entire source code into machine code before execution.
• Produces a separate executable file (C, C++)

Interpreter

• Translates and executes code line by line at runtime.
• Slower than a compiler but useful for debugging (Python, JavaScript).